Science-Jazz & Humanism

The Fusion Steam Machine

A Fusion Reactor for Today

In this article I will present a nuclear fusion power plant which is instantly buildable with todays technology, which is much safer than any of todays working nuclear power reactors, which provides enough hot steam for electric power within the GW range, which provides at least 95% fusion energy, which has a 7.5 times higher fuel efficiency than todays fission reactors and consumes totally at least less than 1/150 of natural uranium than nuclear energy production today, which produces no nuclear waste to be removed, which uses raw natural uranium-238 and ordinary ocean water as basic materials for energy production, which breedes and produces it own nuclear fission and fusion fuels within the plant, which costs less than any of todays nuclear energy plants, which can provide electric energy for less than 5 Cent/kWh for the end consumer.

No new Fusion Reactor Idea

There are so many fusion energy ideas in the world and in the internet. Some of them are multi million dollars projects like magnetic confinement fusion (Tokamak reactors) [1][2][3][4] or inertial confinement fusion (Laser fusion) [5][6][7]. Some of them are smaller research projects. Some of them are even amateur cellar devices for a few thousand dollars, that provide real fusion reactions and this is scientifically repeatedly approved [8][9]. Some of them are just stupid ideas that ignore physical laws but produce nice renderings and Youtube videos. Some of them work, and there is a fusion reaction, some of them not. They all have one thing in common: they don’t produce any net-energy. And they all have a second thing in common: they are far away from doing so [10][11][12][13]. Of course the Tokamaks are closer to a net-energy production than any other attempt. Scientists estimate their energetic break even within the next decades or twenty to thirty years [14]. But even if they reach break even, they seem to be still endlessly far away from economic energy production. There is a nice disertation available in the net that mathematically shows that [12][13]. Economic energy production means producing huge amounts of hot steam per second for giant turbines and gigawatts of electric energy for big cities, as our fission uranium reactors or coal or oil or gas power plants provide for many decades now.

Let’s face it: there is no chance to produce economic electric energy by any of todays fusion approaches within the next decades, if ever [12]. On the other hand is the ubiquitous natural fusion power source: the sun. So many people talk about solar energy as a kind of fusion energy. But that’s just cold comfort. First it seems not to be such a good idea to place the energy transformers 150 million kilometers away from a fusion reactor if you want to economically get energy out of it. Second fusion energy actually means to be independant from the sun, to have an autonomous fusion energy source wherever humans will ever settle, near the poles, on the Moon, on Mars, beneath the ocean, or even on Jupiter’s moons, where no ray of sunlight ever reaches to. Solar and wind energy bind us forever on our planet, and there – more precise – on the continents within a certain lattitude. Very fast we will run short of it. We will only move from oil wars to sun and wind wars: oil, sunshine, wind – any of them – is finally solar energy in different forms. Moving from oil to sunshine and wind is no progress at all. It is very uneconomical because of it’s much lower energy density. The latter means less prosperity for nations that use sun and wind extensive, because the expense for primary energy is – independent of the markets – the basis of the buying power. Primary energy is used to mining the raw materials and harvesting the agricultural crops and to manufacturing all products out of these. This simply means all products become expensive, if energy is expensive. But if we don’t have fusion energy available and our oil and gas reserves vanish as well uranium is getting rare, it seems we don’t have another choice.

But does mankind really has no artificial fusion power source available? No, that’s wrong. Mankind owns an artificial fusion energy source for about 60 years now: the hydrogen bomb. What does it do? It fusions deuterium and produces a lot of energy. Energy that suffices to destroy a big city within seconds. So there should be also enough energy to supply the same city with its complete electric energy needs for tenthousands of seconds. That is simple physics or mathematics. That means we actually allready own the high power source scientists are searching for: that massively exothermic fusion reaction, which any other attempt fails to deliver. Some people are talking about todays fusion attempts as the „holy grail“ of energy research [11]. That’s just nonsense. Their holy grail is still available, it’s the deadliest weapon, man has ever created. More a „Pandora’s box“, if opened, than a „holy grail“. It seems to me we have to put the energy back into the box and dose it over time, if we want to use it. But how to do this?

Nuclear detonations are far too powerful. They release too much energy. They are not controllable. These are some thoughts, I also had at the first view. But guess one of our common fusion developments (Tokamaks, Laser fusion) would finally result in a power plant. How much energy does a big city need? Let’s say 1 GW. How high will the efficiency be from the thermal radiation power to the electric energy. Let’s say 20%. That would be a good value, I’m not talking about the raw turbine efficiency from steam to electric power. So the energy plant has to provide 5 GW radiation energy to get 1 GW electric energy out of it. In one second it is 5 GWs or 5 GJ or 10^9 J. The TNT equivalent for one ton of explosive is 1 T = 4.2 * 10^9 J. So the fusion plant has the same power as if it explodes any second around 250 kg chemical explosives. By the way our todays coal, oil and gas plants with 5 GW thermal energy have to provide the same power. It is really 250 kg that is burned in a second, because the energy of TNT is approximately the same like carbonhydrates-air-mixtures. The only difference: it’s a deflagration and not a detonation and therefor we hear no bang like in a motor of a car.

Now guess we get to fusion by Laser inertial confinement fusion, then we will have again the bang like in a motorcar. Inertial confinement fusion does not work continuously. Guess it will last 15 minutes to install the loads in the vacuum chamber and to evaporate the chamber. Then any Laser fusion energy output impulse has to provide 4.5 * 10^12 J any 15 minutes for 5 GW power, which is a little more than a 1 kT detonation. This is of a size of a tactical nuclear weapon. Guess it will last 1 hour to prepare the chamber and charge the giant lasers, then the fusion energy impulse has to provide 1.8 * 10^13 J or 4.3 kT. If it takes 24 hours to charge the lasers, the plant has to provide 103 kT per impulse to provide 5 GW thermal power or 1 GW for the city. 103 kT is of a size of a strategic thermonuclear weapon. That is the energy any 5 GW thermal power electric power plant of today releases in 24 hours – simple mathematics.

The main problem with inertial confinement fusion of any kind is: the more often one detonates allways smaller loads, the more ignition energy has to be put in the process. There is a limit of the detonation size that makes energy break even possible and a much bigger detonation size that makes the process economic. This actually means: economic inertial confinement fusion will allways have detonations at least of a smaller tactical weapon size. Why are we waiting so long, if we can have this immediately?

There have been first ideas using nuclear fusion in the late 1950s. John Nuckolls [52] designed a fusion power plant that heated steam by means of hydrogen bombs. But the caverns would have collapsed after a while and no one knew how to build them economic but with underground detonations. There was also the problem how to get the detonators through the drilling pipes. In this times fusion detonators were of megaton yield. Today we are able to build the fusion detonators as small as we need them for any kind of power plant size, down to 1 kT and less [54], we have huge tunnel boring machines and have excellent experiences with any kind of big reinforced concrete constructions. I think, it’s time now to build working and very economic inertial confinement fusion power plants! The figure above is from [52].

So, do todays fusion researchers really think their attempts could work without unpleasant side effects? Do they really think their attempts will lead to harmless, gentle, green power plants without deadly radiation, pressure and heat? Of course not, they are physicists. Some populists tell us that unrealistic stuff frequently, when trivializing it in popular scientific articles, but that is far from physical reality. All economically valuable energy sources have in common that they provide a high energy concentration, to minimize the mass of complicated structures converting that energy to electric power. That is why energy from coal, gas, oil, uranium and also water (the energy conversion is highly concentrated, the rest of the structures are big but primitive) is relatively cheap and why solar energy and wind energy is relatively harmless but very expensive (and why solar energy is more expensive than wind energy).

Where a lot of energy is concentrated, there is allways a hazard, because concentrated energy can instantly set free huge forces. This is why all of todays fusion approaches, will once definitely become potentially hazardous, if they ever become economic. At tokamak reactors we have sometimes explosions, if the strong current in the plasma fails that pinches it (disruption) [51]. The only alternative would be: they stay in a state of low energy density like sun and wind and stay – if they produce energy at all – very uneconomical.

And all of todays bigger fusion energy research projects are allready potentially hazardous:

the Tokamak with a) its liquid metal coolant, that explodes at contact with water or air [11][15] b) cryogenic superconducting magnets, that burn up instantly, if their coolant fails [11][16] c) continuous hard neutron emissions from the fusion reaction, breeding radioactive tritium for the process, contaminating and molecularely desintegrating the reactor blanket [11][16], and able to breed plutonium much simpler than breeder reactors do [17] d) disruption of the plasma that stops the large current through the plasma, that is needed for confinement, and lets it explode immediately [51]

It seems that finding a much safer method to breed plutonium-239 from natural uranium-238 than todays fission breeder reactors is the main reason why many countries put a lot of money into the Tokamak fusion reactors. This technology, from which most scientists believe for decades, because of physical reasons, it can never economicaly provide electric power [10][11][12][13], is a very secure and effective way of breeding tritium and weapon-grade plutonium for nuclear weapons or even more reactor-grade plutonium for fission reactors [17]. The goal seems to be to get to the break even – and not more. At break even the Tokamak just produces some small portion of net-energy but a lot of neutron radiation already, that is needed for breeding. Now it can support the breeding processes by itself and no additional energy is needed for breeding plutonium.

That must be the goal of the current research, otherwise the billions of Dollars/Euros that are put into the projects would make absolutely no sense, because the „far goal“ of building Tokamak power plants seems to be beyound the physical horizon [12]. But with a self containing Tokamak breeder reactor the world problem of limited fissible uranium-235 for fission reactors could be solved relatively elegant by breeding plutonium without the need of dangerous fission breeder reactors. Just replace the reactor blanket inner layer metal in the Tokamak throughoutly with uranium-238 and you have the perfect plutonium-239 breeder. Now I really think the Tokamak research is worth it’s money. I can understand why our ministers of scientific affairs don’t shout this from the rooftops. In this video [16] you can watch how to replace radioactive blanket metal parts of several tons elegantly and fast with the help of giant handling robots.

The inertial confinement fusion with lasers (or wire-array Z-pinch) is nothing else than miniature hydrogen bombs. It ionizes the surfaces of the fusion fuel containers and lets compress them by their own plasma release (ablation pressure) just like the Teller-Ulam thermonuclear weapons do [19]. The difference is the primary, the energy source for heating up the surface of the fusion fuel container (thermalization), that is no nuclear fission bomb as in the weapons but many concentrated high energy beams (or X-ray from many thin plasma strings that are pinched). So there is no minimum limit for the primary like in the fission bombs due to critical mass and the mini bomb is limited more due to manufacturing problems. Of course inertial confinement fusion with lasers (or Z-pinch) is the perfect experimental bomb for laboratory research. Research on thermonuclear weapons has probably made many achievements with this research devices in the last decades (this is trivial logic because they were the first experimental laboratory devices at all) but nearly all results are classified. An energy break-even or net-production was absolutely not necessary for that, and there have been very less progress to the „far goal“ of developing a power plant.

Electrons and Ions as energy beams would be much more efficient than lasers as inertial confinement fusion primaries [20] but they are not as well suited for weapons research than lasers that imitate the X-ray of the real nuclear primaries much better. If someone intended to build a perfect laboratory simulation of nuclear bombs they would use lasers as primaries of course. If someone intended to build a power plant and aspired to an energetic break even they would use ion beams because of their much higher efficiency. But that is ok. Inertial confinement fusion plants will allways be very ineffective as energy source if they become a source ever [12]. But if the investigations result in better thermonuclear detonators, we will have available even better fusion energy sources than today.

The truth is: The „far goal“ some scientists are talking about exists since November 1, 1952, when operation Ivy Mike was conducted succesfully [21]: an inertial confinement fusion device of Stanislav Ulams [22] working design with a fission primary energy source [23]. These devices have been tested of yields from the smallest of 1 kT [50] and 10 kT [24] over all sizes to at least 50 MT [25][26] depending on weapon type and of fusion energy percentages from ca. 20% to 97% [25] depending on technology. What, if I tell You now a way to make this dangerous (because highly concentrated) energy source available for civilian purposes – right now? To make a civilian and peaceful machine out of a fierce and dangerous weapon; the long desired fusion power plant of high fusion percentage of at least 95%, simple and cheap. I will show You: the „far goal“ has been right before our faces for the last decades.

How it works

In the underground are four big concrete cylinders. Each cylinder is 200 m in diameter and has a water supply which fills about 1/5 of it’s volume. The cylinder’s roof is at it’s top six hundred meters beneath the surface. A cyclic process starts. Cylinder number 1 is ignited, during some seconds 186,000 t of water in the cylinder is hot vapour of 37 bars. This water vapour reaches an outlet at the top of the cylinder roof, and is piped up to the surface by its own pressure, then through a series of three redundant valves, through a big heat exchanger (A), another three redundant valves, and back beneath the surface to cylinder number 3, that is opposite of cylinder number 1. In the heat exchanger (A) water of a second circuit is vaporized that is used in a big steam turbine (T) with a giant electrical generator (G) to produce 1GW of electrical power. At the end of the heat exchanger all hot steam in the primary circuit coil is liquified again.

Before cylinder 1 was ignited, cylinder 4 provided the hot steam and it was flowing to cylinder 2. While cylinder 1 is now providing the hot steam, remaining steam from cylinder 4 that had not enough power to run the generator at 1GW is cooled in heat exchanger B to be liquified, so that it can be used in cylinder 2 in the next step of the engine cycle.

The quantity of hot steam of one cylinder is enough for about 24 hours. One hour before the time is over, cylinder number 2 is been prepared for ignition. Then after 24 hours cylinder 2 is ignited next, the water in this cavern is vaporized whilst some seconds, builds a high temperature and pressure level, and the steam flows through heat exchanger B, and now back to cylinder number 4. Heat exchanger B now provides the heat for the hot steam to propell the steam turbine. The steam turbine runs completely uninterrupted, the inlet steam distributor in the turbine building just toggled from heat exchanger A to heat exchanger B to provide the steam for the turbine.

The period of energy production by overheated steam lasts again for the next 24 hours. The rest of steam from cylinder 1 is cooled and flows as hot water to cylinder 3 within that time. Cylinder number 3 – full of water now – is ignited, builds up pressure, and is drained through heat exchanger A to the empty cylinder 1, which is now refilling with hot water.

After 24 hours cylinder 4 is ignited and cylinder 2 is refilled. After 96 hours or four days the complete process starts again. This process is cycled as long as the turbine can stand it’s continuous operation – lets say 2750 cycles/revolutions or 30 years.

The water is allways in a closed process and there is no loss of it. This is very important, because the water is getting more and more radioactive with time. The turbine runs without interruption over years as long it does not need maintenance. Maintenance is no problem, because the steam from the second circuit is not radioactive. The main problem is now: How can we vapourize so much liquid water to hot steam within one instant, that it will suffice 24 hours to provide a huge electric power of one gigawatt?

We have some losses in the energy provision line. The loss within the generator and the loss within the turbine. The loss in the heat exchanger and the pipe friction loss from the subterrestrial cylinder to the heat exchanger. And if we want to provide 24 hours one gigawatt on average, it means that we have to start with more pressure than we actually need, because the pressure in the cylindrical caverns falls with time as it expands, and the pressure at the end of the expanding phase has not enough power to run 1 GW and therefore can not be used as energy source.

Let’s say as an assumption we have to provide about five gigawatts thermal energy to make one gigawatt available as electrical energy in the generator. This means our machine has an conservative overall efficiency of 20%. We can not take more than that value although the steam turbine and the generator are highly effective machines, because of the other losses that exist, particularly that of the unused remaining steam that is at least 30% of the total energy. Five gigawatt in 24 hours is 120 million kWh or 4.32 x 10^14 Joule or 103 kT in TNT equivalent. This means we have to vapourize and overheat a huge amount of water.

If we want to provide this energy by TNT explosive we need about 103,000 t (1 kT or one thousand tons of TNT is 4.2 x 10^12 J). That would be a long freight train full of explosives – not impossible but totally uneconomic. But there is a very economic solution for that problem: fusion energy! We take a thermonuclear detonator – a hydrogen bomb. It’s no bigger problem to build thermonuclear detonators of 100 kT with 95% fusion energy and only 5% fission energy. The fission primary stage ignites the fusion secondary stage. Normally the fission percentage in thermonclear weapons is bigger – up to 50% and even 70% fission energy, because they use lots of uranium in the second fusion stage to enhance the yield [27]. But it is no technical problem to reach the same yield with a bigger device without this natural uranium tamper. And there have been several – the militaries call them „clean bombs“ [27] – thermonuclear weapons in history between 85% and 97% fusion energy percentage [25][28][29].

With 100 kT or 4.2 * 10^14 J it is possible to vapourize 186,000 t (water has a vapourization heat of 2258 kJ/kg at 103 kg/m^3) or 180,000 m^3 of liquid water. Water vapour has a density of 0.6 kg/m^3, so 186,000 t would be 310*10^6 m^3. A sphere with 200 m diameter has 4.18*10^6 m^3. Let’s assume the half spheres are connected with a cylinder of 200 m height (with a volume of 1.5 times that of the sphere) and the lower half sphere is full of water so the pressure of the steam should be around 37 bar.

In a cylinder with 200 m diameter 180,000 m^3 of water is only 5.70 m height. Actually the pool would be deeper for cooling, damping and energy distributing reasons, but 186,000 t of the water would be vapourized by gamma radiation and X-ray. This is simply because of the energy conservation law. The rest of the liquid water would occur as spray drops.

How the cylinder withstands the nuclear blasts

A 100 kT thermonuclear in 600 m depth is so fierce, that it would open a spherical cavern of 84 m diameter if detonated in the bedrock. This can be calculated by the empirical laws

h_min = 1300m * (E[MT])^1/3

R = C * (E[kT])^1/3 * (rho * h)^-0.25

from [30] with C = 58 for granite, rho = 2.75 t/m^3 and h, R in meter. The maximum dynamic blast pressure on the wall at 84 m diameter would be the same pressure as the ambient pressure of the stone at that depth, it is approximately 160 bar at a density of 2.75 g/cm^3 for granite (at an overpressure of 55 bar). This is why I have choosen 200 m as a diameter for the cylinders: only a bomb with at least 1 MT yield could blast a 200 m diameter spherical cavern. This means a 100 kT yield bomb would be 10 times too weak to produce enough pressure to widen the bedrock of a 200 m cavern. This is very important to know: it is not possible for a bomb to widen a cavern, if it does not have more than the yield of the bomb that produces it.

But there is a conflict if we have a look on a overpressure and dynamic pressure diagram for a 1 kT standard explosion at 1 atm ambient pressure and practical endless, homogenous surrounding atmosphere [31]:

Other yields than 1 kT are calculated by

r(E) = r(1kT) * (E[kT])^1/3

For an athmospheric nuclear detonation of 100 kT TNT yield the shock wave dynamic pressure will be 2000 bar and the overpressure will be around 400 bar at the side walls with 100 m distance. At the roof with 300 m distance the dynamic pressure will 25 bar and the overpressure will be 15 bar. Nothing can withstand a shock wave overpressure of more than 25 bar, anything will be leveled. This is because crater formation on earths surface starts at 25 bar shock wave pressure [31]. 10 bar kills humans immediately, 3.5 bar causes severe lung damage, 0.5 bar damages reinforced concrete structures [31]. The shock wave overpressure of 400 bar or dynamic pressure 2000 bar means that the outer layers of the concrete walls would be liquified immediately by pressure. For example hydroblasting, that cuts concrete into small fragments and blasts them away works also with 2000 bar dynamic pressure but on a very small area and immediately cooled with water steam [32].

But why is the cylinder not expanding and breaking apart? This is because, the explosion is no athmospheric explosion. If it was athmospheric and there was a single concrete wall in 100 meter distance, it would be of course totaly demolished by 400 bar overpressure and blasted away. But in the underground cavern the bomb is surrounded by concrete or rock and this absorbs it’s energy from the first instant. No one knows how this works in detail, there is no unclassified theoretical model, as far as I know. We only have empirical formulas from several underground tests [30]. At the moment it is enough to know that underground detonations are not as fiercely as athmospheric detonations and to use the well proved empirical formulas for them. I will dare an explanation: It could be possible that the outer stone layer evaporates so fast that there is immediately a huge mass of a heat absorbing stone vapour gas in the cavern that damps the shock wave very well or even blocks the expansion of the fireball in an early phase.

This process would even work without cooling water. It is not needed for damping. The water is actually only needed for having a working medium and for cooling down the concrete walls immediately after they have lost a thin outer layer from radiation heat that they don’t heat up further. The latter is best done if there is more water than the bomb can evaporate by it’s heat so that a huge spray dome or a kind of a mist storm occurs that can effectively cool the concrete walls.

The main problem will be the stabilization of the roof. With any detonation the whole cylinder is blown elastically a few decimeters in each direction back and forth. The roof have to withstand these extreme conditions. This could be realized e.g. with a massive static concrete block construction, where any block can move some centimerters in any direction without endangering the static stability of the construction.

The last picture shows a huge pressure vessel in the deep granite bedrock that can „breath“. The right side of the picture shows it during the building phase, just after the roof has been finished. A „breathing“ pressure vessel means, it will elastically move back and forth dezimeters, possibly meters to any outward direction, when nuclear detonations hit the walls any 24 hours during operation. Of course the bedrock will suffer from becoming kneaded once a day. Therefor a special roof construction is needed.

For protecting and stabilizing the building site a first classic roof is build from the top to downward direction. It is not self-supporting, some colums support the roof. In the picture it is the brick-like roof. The „bricks“ are reinforced with screws. Then the blocks of the baseplate ring for the actual roof are cast. The actual roof is a conus of armored concrete blocks with a hole at the top which sits on the baseplate ring. The conus blocks are made of armored concrete. The blocks are cast part for part within the cylinder and replace the first roof. The conus is as massive that it can prevent collapsing the cavern even if the stone above gets a high porosity with the years. The roof construction is dimensioned for 150% overload and will be tested with 200 kT before it starts operartion at 100 kT.

Huge concrete blocks are cast that form the upper part of the pressure vessel and distribute the pressure of the detonations to the roof construction in a controllable manner. Any part of the roof construction is moveable some meters back and forth. It is also important that all blocks are as thick as possible, because when they jump back from the weight of the bedrock after they were pushed outwards, they will hit and hold together at their long sides. Only very thick longitudinal sides can take that loads. This is why the baseplate ring blocks have a very wide base, because they have to distribute the load from the oscillating rock massive on top of the vessel. The concrete blocks can have metal surfaces on their longsides, that are more elastic than stone, distribute the loads better and do the vessel seal additionaly.

The lower part of the pressure vessel is a simple rock cavern made with dynamite blasting techniques. If there wasn’t that heavy loads that will let the vessel „breath“, the whole pressure vessel could be build just by blasting it out the bedrock and reinforcing the roof. But our nuclear blast containers, our Pandoras boxes or motor cylinders, or steam boilers, or rock caverns, or breathing lungs need that costly special roof that literally jump up any 24 hours.

The shape of the cylinder is more like a pear than a perfect cylinder. This is to get the plasma-fireball in a preferential downward direction. With any detonation some milimeters of rock and concrete ar ablated from the fiery X-ray emission of the detonators. Because the cooling is instantly active by spraying several hundred thousand tons of water mist onto the walls, the ablation can be reduced to the minimum: the pure radiation ablation. Because of the cylinder shape the detonations will dig downwards with time. I designed this to preserve the roof for a very long time. If the concrete walls are thick enough, it could be possible to run the cylinders for centuries, until the ablation reaches the roof conus and the operation of the plant has to be stopped.

Damping, Cooling and Directing Nuclear Blasts

Normally an athmospheric nuclear blast expands spherically. The plasma fireball ionisizes air to electrodynamic plasma, the plasma expands as far as the surrounding pressure of the air allows it. From the outer limits of the plasma ball a spherical shock detonation wave expands, that is reflected from the ground. The surrounding compressible air damps the shock wave very well by heating, that the wave looses it’s pressure peak much faster than from a pure geometrical point of view (by the power of 3). [31]

The maximum diameter of the fireball in the athmosphere (air at 1 atm) is

Dmax = 150m * (E[kT])^0.39

For a 100 kT detonation it would be 900 m at 1 atm.

The effective temperature of air is at the maximum diameter

Teff,mas = 9000 K * (E[kT])^-0.04

For a 100 kT detonation it would be 7500 K or 7200 °C. These are typical values for air as the surrounding medium [31]. Nuclear underwater explosions are even much more desastrous.

Underwater detonations of nuclear bombs are very effective. There have been tests in shallow water [41] and in deep water [42]. The fireball ionizes water to a plasma bubble, it expands as the surrounding water pressure allows it and further. After a short time the bubble has a much lower pressure than the surrounding water pressure and implodes until the pressure is again much higher than the surrounding pressure and it explodes again. This can occur several times until all energy has dissipated to heat. From the outer limits of the plasma bubble every time a detonation wave expands that is nearly undamped in the incompressible water and hits targets (particularly submarines) heavily. The speed of sound in water is four times higher than in air and so the propagation speed of the shock wave pressure [31]. The high environment pressure of deep underwater explosions let’s the nuclear blast shock wave maximum pressure increase linearly with that depth [31]. This is an easy way to get to a very effective shock blast weapon that destroys submarines in a wide area of an ocean.

Underground detonations are the opposite to underwater detonations: they are very ineffective as weapons. When project Rainier [43], the first underground detonation of a nuclear bomb, was conducted on September 19th, 1957 geologists all over the planet were informed about the exact time and listened with their seismographs. To their complete surprise they detected not as far the strength they had assumed. Later ist was found out that the melting of the stone and producing of lava damped the explosion very well, because it consumed much of the energy. The rock around the explosion center was very hot for many months, that it was not possible for workers to reach the center. The heat radiation limited the working progress, not the radioactive radiation. It was found out that the nuclear radiation was very well enclosed in the lava and the detonation cavern was by far less radioactive than assumed. [33]

But stone is incompressible like water. Beyond the fireball should be a strong seismic shock wave that runs through the bedrock. What is the difference? First the melting (around 2 MJ/kg) and vapourization heat (around 14 MJ/kg) of the stone is much higher than that of water (330 kJ/kg, 2200 kJ/kg) so that it consumes around 6 times more energy per mass. The density for granite is typical 2.75 t/m^3, this means the stone consumes around 16 times more energy per volume than water. Second the dissipation rate is much higher because the vapourized stone can not oscillate between liquid and vapour like the cavitation of water can do. Once vapourized the stone will not liquify as it was before. The material will be dissociated by the heat and will remain in separate fractions when liquifying again. Nevertheless the detonation of Rainier weakened the rock in a wide radius around the detonation center with cracks and disruptions and the roof of the cavern collapsed after a short while.

Damping

I will explain the damping of the detonation inside the vessel, as I imagine it, but this might not the ultimate truth:

The damping of air or water steam in the vessel can be neglected. The extreme X-ray radiation vapourizes instantly the rock and concrete outer layers and let a blast of vapourized stone push on the expanding fireball. This blast is so strong that the walls are elastically pushed outside by their own inward gas flow (just like rockets at lift off).

The shock wave from the detonation hits the gas front from the stones. The chemical reactions in the stone gas consume more energy than it would be in air, because it is mostly irreversible, thereby damping the shock wave effectively. When the shockwave hits the walls it is still strong enough to decrease the stability of the surrounding bedrock, by damaging the rock. Therefor the stabile roof is needed, which is as far away from the detonation that it’s armored concrete will resist the shock wave.

The expansion of the fireball is also retarded by the stone gas and it doesn’t hit the walls as it would do in the free athmosphere. When it had 160 bar at 42 m distance (from the 84 m cave diameter of a 100 kT underground detonation) it should have approximately 160 bar * (42/100)^3 = 12 bar in 100 m distance at the walls, 44 kPa in 300 m distance at the roof and 1.6 kPa in 900 m distance at the surface, assuming an undamped geometrical thinning of the wave. Windows burst at 1.4 kPa. So there should be no buildings and no personnel on top of the cylinders when detonating. Well Armored concrete withstands 44 kPa without a problem, so the roof will persist stabile. At 20 bar anything will be flattened, at 25 bar craters will be formed. So with 12 bar the side walls should remain. If the 44 kPa at the roof is too much from standpoint of thousands of cycles during decades, the pressure vessel has to be build higher.

The turbine building, the generators, the transformers and the control building should be at least in 1.7 km distance from the cylinders, where the entrance to the tunnels lie, and where definitely nothing more than a loud bang from the surface reaching shock waves will happen. People in the next city in some ten kilometers distance can’t feel or hear anything of the shock wave or the seismic oscillation from the atomic detonation any 24 hours.

Cooling

After the fireball fills the whole cylinder the heat of the plasma shall be compensated by 180.000 t of water that also takes the radiation heat from the concrete walls that were liquified (lava) within an outer layer and otherwise would now begin to flow and drop downward. If there was no water in the cylinder the concrete walls would take the total heat of the radiation plus the fireball and some decimeters of concrete would melt. This can be prevented by cooling the concrete walls immediately by water steam.

But steam alone may not be effective enough. There should be more water in the cylinder than the 180.000 t that are to vapourize. Then a spray of water and steam would occur as a very heavy rain storm inside the cylinder, that should be very good to cool the concrete walls.

Directing

The Casaba-Howitzer weapon (there is only one – very fictional – site in the whole web with a realistic visualization [34]) forms a nuclear energy plasma to an energy beam by using a flat sheet of metal, that is vapourized by the explosion. The energy beam then leaves the vapourized sheet metal in orthogonal opposite directions. It can be calculated by means of electrodynamics that the thinner the sheet is, the more focused is the beam. The nuclear pulsed Orion spaceship design used this technology for the first time to give the pulse blasts a predominant direction [44]. Later it was proposed and investigated several times for means of ballistic missile defence from space, e.g. project Excalibur [45].

The fusion steam machine as proposed here could use the same approach. Maybe it would make some sense to direct the plasma fireball to a more ellipsodial shape that fits better in cylindrical caverns. This could possibly be used to distribute the pressure and heat more equal to enhance the durability of the concrete cylinders.

The Four Stroke Thermonuclear Motor

I call this design also the Four Stroke Thermonuclear Motor because the plant is in principle a giant four stroke motor running in slow motion that is not heating air with chemical explosions but water with fusion power:

The first stroke is to install the nuclear device in the underground lake, similar to the intake stroke of the motor.

The second stroke is the explosion and thermal compression similar as the motor does in the compression stroke.

The third stroke is the expansion through the heat exchanger and the turbine and producing of primary mechanical rotational energy similar to the expansion stroke of the motor.

The fourth stroke is leveling of the cylinder pressure similar to the exhaust stroke of the motor. This is done by relaxing the rest of the steam and liquifying it before it enters the cylinders again.

In the motorcar any of the four strokes lasts 10 ms at 3000 rpm (the four strokes need two revolutions of the crankshaft). In the subterrestrial Four Stroke Thermonuclear Motor it is 1 hour, 10 seconds, 24 hours and 23 hours. This is 12 hours in average and 4.3 million times longer than in the motorcar. A motorcar has a typical cylinder volume of 0.5 liter at 25 kW per cylinder with hot air as working medium at 10 bar. This is 50,000 W/l or 5000 W/l/bar for the motorcar. The equivalent typical Four Stroke Thermonuclear Motor cylinder volume at 5 GW with steam as working medium at 37 bar is 8.3 billion liter. It is 0.6 W/l or 16 mW/l/bar. Which motor is more extreme?

I had designed a Four Stroke Thermonuclear Motor for use on the moon before [35], but it occured that the bedrock was not able to absorb the residual heat in a long time fashion and I wanted to get rid of the radiators and designed another version of a fusion steam machine for the moon: the Nomad Fusion Reactor [36] which eleminated the need for radiators. But on earth the Four Stroke Thermonuclear Motor works very well without radiators, because there are several alternatives of heat discharging methods:

air cooling

water evaporation

using river water

using ocean water

The needs for computers are very low in this project. Of course they can make any step more efficient and more automatically, but actually you don’t need any computers for the plant. Actually any step of the process can be done manually and unhurriedly. This fusion energy plant is truly simple. It could have been build – from a technologically view – long before the computer age, just after the invention of thebomb. But it seems to me, that no one wanted it, and only a few people were thinking about using thermonuclear bombs for civilian purposes . And this is no wonder, it is a scary and strange device that stores the whole energy demand for a big city for 24 hours in just a few kilogramms and sets it free in seconds. And I was scared, too. But meanwhile I’m deeply convinced that using thermonuclear detonators (todays devices and more effective detonators of the future)

will unerringly be allways the most effective way, and

will possibly be the only way for evermore

to get to economic fusion energy.

What I have just explained in this text is a 4 Cylinder Four Stroke Thermonuclear Motor. It is also possible to build a 6 Cylinder Motor or a 8 Cylinder Motor and so on. But a 2 cylinder variant is not possible (it would work only 50% of the time) and uneven numbers of cylinders are also not possible.

The Savety of the Plant

In two older texts I have expressed my oppinion that such fusion power plants can not build on earth. They had to build on the moon because of three reasons:

nuclear proliferation

public health hazard

ultra high bomb yield

I have redesigned the machine to a modest detonator yield of 100 kT now, that suffices for providing a big cities energy needs for 24 hours and that is manageable with buildable artificial rock cavernes made with standard non-nuclear bedrock engineering technologies, that don’t contamminate the environment.

The public health hazard of the revised version of the plant is much lower than that of todays uranium reactors and much lower than the planned Tokamaks, and if society dares to operate such widely accepted plants, it can also operate my fusion steam machines. And I have planned the detonators non-storable:

The nuclear proliferation problem still exists. But it can be reduced to a minimum, if the plant breeds it’s own plutonium-239 from natural uranium-238 just in time. The plutonium is needed for the thermonuclear primary pits. If they are produced in the plant just in time, together with cryogenic non-storable chemical explosives and cryogenic non-storable deuterium secondaries, there should allways be not more plutonium available than for just one 5 kT nuclear bomb. And I’m talking about the plutonium, not the chemical detonation system. This is important, because the detonating implosion system will be not storable and therfore not transportable. This is the same for the secondary fusion stage of the detonator. So the nuclear proliferation danger can be minimized to a manageable risk lower or maximum as big than that of common breeder reactors.

The Four Stroke Thermonuclear Motor has a higher operation safety than any of todays nuclear power plants. It is also much safer than any of the planned fusion reactors like the Tokamak reactor. There is one important difference between it and all of the other reactors: the off-button.

In any situation it is allways possible to stop the steam flow simply by closing one of the redundant closing valves in line on top of the cylinders. Nothing happens then. The steam flow just stops, the turbines and the generators stop. If there was any malfunction, it can be fixed unhurriedly. After the incident the valve is opened and the steam flows with the same pressure and temperature as in the moment it was stopped. If neccessary, it is also possible to abolish the working pressure in the cylinder controlled and let it flow into the other cylinders, cooled or uncooled.

There is no danger of leaking containment. The vessels are so deep in the rock, that the extreme pressure of the stone closes all cavities or cracks. Of course the rock is weakened by the detonations and becomes with time very „porous“. This geological term of porousity only means the mechanical properties at this depth. The stone becomes less stabile and the roof has to be designed for that. But the stone does not become permeable for the radioactive steam. All investigations for the containment of former underground tests in the USA, even at extreme porous, sandy geologic formations, have shown that [39]. Even soviet nuclear explosions that were – from a radiologic point of view – conducted not that carefully, showed no meassable escape of radioactive gases [40].

It must be clear, that „breathing“ pressure vessels that oscillate together with the rock massive on top of them and that are tested with 200 kT bombs inside will withstand nearly any natural earthquake. The redundant closing valves are located in underground bunkers that withstand nuclear wars. There are only a view scenarios, where the contaminated steam from the pressure vessels will escape uncontrolled: e.g. asteroid hits and direct megaton bomb hits that both destroy the closing valves bunkers. But in both cases the reason for the leakage is worser than the leakage itself.

The plant uses a primary water circuit that connects the cylinders with each other, which is a simple pipe with redundant closing valves at the cylinder outlets. The steam turbine is connected to the secondary non-radioactive water circuit that is heated by means of simple heat-exchangers from the first water circuit. Savety first, this recuperator is of a simple geometry.

The Four Stroke Thermonuclear Motor doesn’t use extreme dangerous fluids like the Tokamak or the fast breeder reactor. They have to use liquid metal as a coolant, because of physically reasons, that burns instantly with water or air. It doesn’t rely on a magnet field to confine the fusion plasma in a high vacuum, it just uses water and water steam to absorb the fusion plasma. No parts have ever to be replaced because of neutron radiation decay, like it is planned with the whole core in the Tokamak by using giant manipulation robots. The quantity of accumulating nuclear waste is insignificant. The waste can remain in the cylinders as sediment, without disturbing the process. So it is not neccessary to ever open any of the highly radioactive parts of the plant. This means, there will be no radioactive hot zone in the plant. The only radioactive parts of the plant are the two crossing cylinder connecting tubes with their spiral radiator loops on each side.

The plant doesn’t need time to cool down, when switched off, like normal uranium reactors need. There is no danger with overheating cores or detonating hydrogen gas, like in uranium reactors. Cooling water loss is no danger any more because cooling water is only needed for thermodynamic efficiency reasons. If there is ever measured radioactivity at the plant area, the closing valves are closed, no more radioactivity will escape, and the search for the leakage can be done unhurriedly.

Nuclear Waste

Nuclear detonators of 100 kT yield weigh around 100kg. Their material is evaporated completely during detonation and builds-up as partly radioactive slag on the ground of the water basins with time. If a detonator is ignited any 24 hours. It is 3650 tons of slag in 100 years. That is at an average density of 7.9 g/cm^3 (steel) a volume of 460 m^3. At four cylinders it is 115 m^3 per chamber. With a cylinder diameter of 200 m and a flat cylinder bottom it is a 4 mm film in 100 years. With a half sphere bottom of 100 m radius it is a 11 m radius pool with a maximum depth of 60 cm in the middle of the pool.

On top of the partially radioactive sediment is the water pool with several hundred thousand tons of water. Any time a detonator is ignited a blast wave runs through the water with the speed of sound and smashes anything into particles that is not at least in 100 m distance of the center of the cavern and a several meters concrete wall. So highly radioactive particles will allways get mixed into the water and the water will become more and more radioactive with time until it reaches a maximum radioactivity when decay rate and increase of radioactivity are ballancing. But the radioactivity of the steam will be extremely high and so no other movable parts than the redundant closing valves shall interrupt the pipes between the cylinders.

It is possible to run the plant hundreds of years without the need of ever removing the water or the slag. The plant generates no nuclear disposal, it becomes its own radioactive waste repository during a very long time. The waste is thereby automatically supervisioned by the plant personal. In commercial nuclear waste repositories this is a service energy providers and/or the public have to pay for. The motor cylinders have thick concrete walls of several meters and are 600 m deep beneath the surface. The cylinders withstand internal 100 kT nuclear blasts – there is no better radioactive waste repository possible.

The cylinders are an ideal containment in that depth, as detailed and carefully conducted measurements at former US and soviet underground test sites resulted [39][40]. Scientists didn’t find traces of radioactive gases on the surface, although the radioactive gases once had a pressure of several hundred bars. The rock seems to be a perfect containment at depths of several hundred meters and more. In our case it is even better, because after the last cycle of the plant, after the turbines are shut down forever, there will be no overpressure in the vessels from steam. They will be filled simply with hot water and the heavy highly radioactive substances will sink down.

There will be the possibility to measure the decay rates safely by descending probes through the former outlett pipes. It is also possible to cool the repository, if the decay produces more heat than predicted, just by cooling the developing mist atop the water plane with the heat exchhangers on the surface by pumping the mist from one vessel to the other. If following generations need radioisotopes as basic materials they just pump them from the bottom of the vessels. This are three features todays nuclear waste repositories don’t offer. The fusion steam machine is it’s own nuclear waste repository, as I said, but it is also the perfect nuclear waste repository – controllable, measurable, accessable.

How to build the Plant by todays Civil Engineering Means

Building the plant means building at least four artificial cylinders of 200 m diameter in 600 m depth. A practical and economic way to do so, could be that: two of the biggest tunneling machines dig two parallel tunnels of 10 m diameter at an angle of 20° into the ground until they reach 600 m depth. The tunnels start at 1.6 km distance and are of 1700 m length. The machine drills 5m per day. After 340 days it reaches the deepest point and will now be steered to a wide radius that it circles two of the cylinders, and goes up again, parallel to the first 1700 m long tunnel. The work on the cylinders can therefor start after 340 days or 11 months. After 22 months the work goes several times faster, because from now on trucks can enter the building site from one access tunnel and leave it throug the other.

On the top of the cylinders they have steam outlets. This is a normal drilling pipe that is build by a typical drilling rig. Several close valves in line, in a bunker, just below the surface, 600 m on top of the cylinders, enable a very save switch-off-anytime functionality.

The cylinders are build from the top of the cylinder to the bottom by blasting the rock with chemical loads. First the upmost cavern (A) is blasted and reinforced, then B, then C, D, E. Then the inner rock dome is blasted and the baring is carried away. Finally the bottom is cast.

The caves are stabilized by several meters thick walls of concrete, their roofs are of spherical or conical shape. When hardening the concrete cylinders are pressurized that they will later conduct all pressure directly to the surrounding bedrock.

The concrete walls have to withstand huge shock waves. Because the bedrock will respond elastically, the concrete walls have to be elastically too. Therefore they have to be built like blocks that fit perfectly together and to the wall behind them. So the concrete wall can move outward a little, moving the bedrock outward and spring back without falling apart. The outer layer may be blasted off, when springing back. Therefor the wall bricks have to be reinforced several times and have to be very thick that they can withstand massive errosion for at least 100 years or 9,125 cycles.

It must be clear that the operation of the pressure vessels with 100 kT thermonuclear bombs can not be nondestructive. The goal is not to build them that they can not be damaged, the goal is to build them that the damaged pressure vessels will still keep the cavern from collapsing. The most vulerable part of the cavern is the roof, this is why it has a three times higher distance from the detonators and 27 times less shock wave pressure than the walls of the cavern.

Detailed analysis should find an optimum geometry for the cylinders as small as possible to reduce the building cost but also as durable as possible to allow the reuse of the cylinders after the nominal lifetime of the plant of 30 years by just replacing the turbines and generators. Ideally the durability should allow cumulating lifetimes in the centuries range at sizes that are still practicable with todays civil and underground engineering technologies.

After the cylindrical pressure vessels are built, they are flooded with water. The 10m access tunnels from the main ring tunnel to the cylinders are narrowed with liquid concrete and a redundant pressure lock is built in to enable a comfortable and reliable remote controlled assembling of detonators and breeding uranium into the cylinders.

While building the cylinders in the underground a plant is build on the surface at the entrance of the tunnels in 1700 m distance. It has two primary steam circuit pipes that connect two opposite underground cylinders each. Heat exchangers connect the secondary steam circuit with the primary steam. The secondary steam circuit propells a power turbine that is located in a turbine building and drives a generator. The generators electric power is transformed to high voltage and supplies the next city with 1GW of electric power. The turbine can switch without interruption between both heat exchangers as steam input. All coolant water of the plant is finaly cooled in cooling towers by condensing water from a river. If the plant is built near an ocean the ocean water is used to cool down the coolant water of the plant.

The building of the power plant has much in common with building water power plants, where long tunnels [46] of huge diameters are also very common as well as concrete vessels and giant underground caverns [47] in the bedrock. In the oil industry there are also projects of very big concrete vessels [48].

Cost and Economic Importance

Let me try a first raw cost estimation. I will take the numbers of typical experienced data in civil engineering and raise them to the next round sum. The two big tunnels can be built at a maximum of $ 150 Mio each (5 km, $ 30,000 per meter) [49]. The four huge caverns should cost not more than $ 100 Mio each (8 Mio m^3, $10 cost per cubic meter for blasting and excavation, $ 20 Mio for the temporaly roof). The underground 4 roofs shall cost $ 100 Mio each. The turbine with the turbine building and the generator should cost not more than $ 500 Mio. The four heat exchangers and the highly reliable primary steam circuit shall cost another $ 100 Mio. The rest of the plant shall cost $ 100 Mio. This is together $ 1.8 billion for the power plant and is rawly in the prize range of cheap natural uranium high temperature reactors or five times cheaper than modern pressurized water reactors in the $ 7.5 billion range.

The plant generates no nuclear disposal, it becomes its own radioactive waste repository during a very long time. So there’s no cost for disposal. The cost for the military-derived 100 kT detonators used in the first test phase may be $ 1 Mio each. That generates a cost at 1 GW in 24 hours of 4.2 cents per kWh.

If we decide to build civilian cryogenig non-storable, non-transportable detonators in the plant, we have to invest in a process engineering facility that provides technologies like electrolysis, nuclear handling, centrifugation, cryogenics. This will also cost a lot, but may be much cheaper than buying the detonators from the military production facilities. In the next chapter I will explain what kind of detonators the plant actually need. They will be very cheap, non storable and will have no military relevance. Let’s assume the cost for natural uranium is $100 per kg, for the other metals it is $10 per kg. The detonator weighs 100 kg, 5 kg of it are made of plutonium breeded from natural uranium. Let’s further assume the plant breeds it’s own plutonium for the detonators primaries and builds the complete cryogenic detonators in a special facility. 3 shafts of 20 highly skilled workers each at $50 per hour shall work 24 hours on one detonator. Then it should be possible in a series production with a daily output of one detonator to produce it for less than $ 30,000 per detonator. That would reduce the cost to 0.13 cents per kWh. Let’s assume the detonator production facility costs as much as the power plant, $ 1.8 billion. The life time of the turbines shall be 30 years and the plant produces 260 billion kWh within that time. Then the cost for the plant plus the production facility would be $ 3.6 billion / 260 billion kWh or 1.4 cent/kWh.

This all means: even in the test phase the energy will be as cheap as waterpower. In a later more advanced version the plants will become the cheapest energy source mankind ever built. Cheaper than those dangerous natural uranium fission reactors because of much higher simplicity, the omitted nuclear waste disposal cost and the much higher average utilization time of nearly 100 %.

If the size of newer plants becomes bigger with time, the energy cost will fall further. It will fall below 1 cent/kWh cost and lower than 5 cent/kWh for the end consumer. That means the energy cost for all products and all basic materials will fall to a fraction of todays cost, that means a negative inflation. Our money will have indeed much more buying power, the prosperity will grow as fast as never before.

The Detonators: No Weapons

The planned thermonuclear detonators for the plant consist of a primary with 4.5 kg plutonium-239 of 5 kT yield and a cryogenically frozen deuterium secundary of 100 kT yield without a so called spark plug and with a tungsten or lead tamper. The primary is imploded by chemical explosives. They are made of a stochiometric mixture of liquid oxygen and methane. Hydrogen and the oxygen are produced by electrolysis from water. Hydrogen methanation is used to produce methane from hydrogen and carbon dioxide. The heavy water for the deuterium is extracted with centrifuges, also directly in the plant. Deuterium is produced by electrolysis from heavy water. The plutonium-239 is breeded inside the motor cylinders during detonation of the bombs. The bombs emmit massively neutrons that convert natural uranium-238 metal sheets to plutonium-239 sheets.

This is the goal for the detonator production. The enriched plutonium-239 shall never leave the plant area, and there shall allways be a small ammount of plutonium, breeded just in time. This is important to reduce the risk of misuse, because there are 365 detonators each year to build and to fire. The planned thermonuclear detonator is no weapon, because it is completele cryogenic and melts without extensive cooling within a short time. It’s planned to be extremely cheap to reduce the cost of the energy to the raw natural uranium-238 cost, and not to be easy to handle and store, that are military requirements.

Plutonium-239 has a critical mass of 4.5 kg, when the neutrons are reflected by steel or another appropriate material. It is assumed that modern thermonuclear warheads are build precisely enough and symmetrically enough that they don’t need spark plugs for their secondary fusion loads [37]. This can be indirectly confirmed, because the neutron bombs of the eightieth (Mk79 warhead) were in principle also 2 stage thermonuclear bombs without a spark plug and without a uranium tamper [50]. Approximately 0.1% of the rest energy E=mc^2 of matter is set free with fission, this is 9*10^13 J/kg. In a D-T boosted nuclear plutonium bomb theoretically up to 29% of the material can be fissioned. So it is theoretically possible to reach a yield of up to 4.5kg*0.29*0.0008*c^2 = 9.72*10^13 J = 23 kT. Practically it is about 5 to 10kT. With this primary it is possible to ignite a fusion secondary of typically 20 to 50 times the yield of the primary. Normally the yield of a weapon with uranium-238 tamper is about 2.5 times more than with a nuclear inert tamper. So the secondary should be of about 20 times more yield than the primary or 100kT to 200kT. Let’s assume we build clean bombs with a boosted 5 kT enriched uranium primary and 100 kT total yield.

Today no country owns such thermonuclear detonators for throughoutly civilian purposes, of course. But it is possible to build a fusion power plant right now and to start with using military plutonium-239 primaries with standard chemical explosives and military secondaries with solid lithium-deuteride fuel, with a plutonium spark plug and without a natural uranium tamper but a lead or tungsten tamper. For a test period of the plant this could be an appropriate approach before research is done in the new field of cheap, clean and safe civilian cryogenic thermonuclear detonators.

A more civilian detonator for power production could still use the military primary but a cryogenic secondary with liquid deuterium, tungsten or lead tamper and no spark plug. Because it uses no spark plug, it needs like the primary a tritium-deuterium gas. In this case not to boost the nuclear reaction by neutron radiation but to make fusion possible at all, because deuterium and tritium fuse 100 times easier than deuterium alone. When the deuterium-tritium gas ignites it will also ignite the raw deuterium surounding it.

A complete civilian detonator for power plants would als use a cryogenic primary. This means the chemical explosives for the primary are cheap cryogenic liquids. This together with the cryogenic secondary makes the detonator very bad to handle and impossible to store. The fuels are allways evaporating, and when not refilling fuels all the time, they will vanish after a short time. Liquid explosives are very dangerous, when once mixed. So the mixing of the two liquids oxygen and methane starts just a few minutes before detonation by means of some valves and pumps in the diaphragma that separates the liquids.

It is also possible to build three stage detonators in that way. The picture above shows a three stage detonator that is built on a 100 kT platform with 95% fusion and enhances it to 500 kT yield with 99% fusion energy percentage. The third stage can be increased from 400 kT yield to 2 MT yield without bigger technical problems. This means these 3 stage detonators will reach from todays biggest nuclear power plants around 5 GW up to future 20 GW power plants.

Our „far goal“ is the pure fusion detonator. A detonator which uses other 5 kT primaries than plutonium-239 fission bombs. This 5 kT primary could be e.g. a small fusion detonator of 5 kT with it’s own 0.25 kT primary made of 6 milligram antimatter (today this is a technically impossible huge amount of antimatter), or e.g. a complicated arrangement of five or more stages of allways smaller fusion detonators down to a size where chemical ignition in the hundred kilogram range becomes possible. But there are many more ideas to get to the pure fusion detonator.

A Schedule to Fusion Power

I will present now a schedule to get from now on step by step to 1GW 90% fusion power plants within 4 years, 95% within 6 years, 99% within 11 years and possibly 99.99% clean and pure fusion within 30 years. In my oppinion this is the pragmatic and realistic path to fusion energy:

2043 (clean pure fusion 100%) first successful tests of 1 kT, 10 kT and 100 kT pure fusion detonators with 100% fusion energy, without fission products of high radioactivity, developing of applications of pulsed fusion power in many classic fields and new fields with high energy needs

Examining the available artificial fusion energy sources of today (warheads) we recognize, they can fastly rebuild to cleaner devices (90% fusion) with removing the uranium tampers. The next step should be to develop a throughoutly cryogenic civilian version with higher fusion percentage, of todays maximum possible cleanness (95% fusion), that has no military value, because it is not storable and transportable, but that is very cheap in series production.

Because of the high neutron emission of fusion reaction the plant is able to breed it’s own nuclear fuel for the fusion bomb igniters from natural uranium. This means, if the detonators production is in the plant, the plant needs only natural uranium and water as basic materials for the nuclear fuels.

Bigger plants with bigger three stage detonators of 500 kT can easily reach 99% fusion power percentage. This can be successively increased to 2 MT by building bigger plants with 99.75% fusion percentage. But the radioactive contamination within the cylinders and primary circuit pipes remains the same because of the same ammount of plutonium and its fission products from the 5 kT primary, although the plants are the best radioactive waste problem solution ever. To overcome this long time problem and for becoming able of using pulsed fusion power for engineering application in the atmosphere, in outer space and under water without harm for public health and for nature a big research program is needed to develop pure fusion detonators without fission primaries.

If the research program for pure fusion detonators is successful, it will produce hundreds of applications for pulsed fusion power in many fields like astronautics, mining, civil engineering, geology and supplying new developed fields with sufficient power: e.g. geoengineering, terraforming or asteroid-mining.

But even if the research for clean and pure fusion fails, mankind will still have 95% to 99.75% fusion from ordinary ocean water and only a small percentage of common natural uranium for igniting the fusion reaction (with 7.5 higher fission efficiency than todays fission reactors) that will reduce the natural uranium-238 consumption from 1/150 to 1/3000 of todays, and rarely fissionable uranium-235 is never needed any more. This means practically an endless energy source for mankind, buildable today.

Summary

Fusion energy is available for 60 years now. I have presented a simple method to make this power source available for civilian electric energy production. The plants are very save: they have a built in switch-off functionality, that other nuclear plants dont’t have. The plants are as ecologic as a nuclear power plant on earth can be: they are their own radioactive waste repository, that withstands 100 kT blasts, no waste have ever to be extracted and transported. The plants are very cheap: even in the test phase with adapted military detonators their energy costs as less as water energy, in a later development phase the energy cost will underprice anything, even cheap (and dangerous) high temperature natural uranium reactors.

Today France, China, Great Britain, Russia and the United States own thermonuclear fusion weapons (India and Israel probably own fusion weapons) [19][38]. These countries can anytime start building fusion energy power plants with the off-button, if they want. Does someone still think the financial and technical risk is to high, the power concentration is to huge, the cylinders will collapse? Then begin the test phase with a smaller 10 kT version with 100 MW for the end consumers.

[13] T.H. Rider writes 1995 as a final conclusion in his dissertation: “As a final point, it is very important that the ultimate goal of this entire field of research [note: fusion energy research] should not be forgotten. The stated goal for fusion for over half a century has been to produce large quantities of clean, safe, affordable, and essentially limitless power for the world. If, after a detailed examination [note: he means his own dissertation] of all forseable approaches to fusion, it does not seem at all likely that the technologically feasible types of fusion reactors can meet this goal, then energy research should instead concentrate on improving other power generation methods such as fission reactors, solar energy conversion and fossil fuels.”

[23] Ulam actually developed a bigger two stage fission bomb, therefor he invented the tamper-pusher ablation driven second stage to detonate much more cheap natural uranium-238 with the uranium-235 or plutonium-239 first stage. [„Die Bauart wurde von Ulam für Atombomben großer Explosionsstärke entwickelt; erst nachträglich wurde erkannt, dass sich damit auch Wasserstoffbomben konstruieren lassen.“, from http://de.wikipedia.org/wiki/Kernwaffentechnik] When Teller, the leader of the Los Alamos fusion bomb project at that time failed with his first design, Ulam proposed Teller to use his tamper-pusher design. Together they modified the design to a fusion bomb. Edward Teller, a person of complicated character, thought it was his own idea and never missed a chance to tell nearly anyone that he had the biggest part on it. Some authors today start to rename the Teller-Ulam design to the „Ulam-Teller“. The russions call the Teller-Ulam design „Sakharovs 3d idea“. Sakharov was the creative head of the soviet fusion bomb development, but at that time the KGB had infiltred the US Los Alamos nuclear weapon program with an agent. Before he was identified he got into the first fusion bomb discussions and so no one knows if Sakharov had the idea independant of Ulam, that is possible, or if he at least was inspired by some basic thoughts from Los Alamos that were communicated by the soviet secret agent. [Charles Seife: Sun in a Bottle – The Strange History of Fusion and the Science of Wishful Thinking, http://www.amazon.com/Sun-Bottle-Strange-Thinking-ebook/dp/B001IH6WOM ]

[51] If the current in a Tokamak plasma drops momentarily, the plasma suddenly looses it’s pinch and explodes in all directions. This is called disruption. One disruption at a modern british Tokamak made it jump 1 cm into the air. It’s weight was 120 tons [Charles Seife: Sun in a Bottle – The Strange History of Fusion and the Science of Wishful Thinking, http://www.amazon.com/Sun-Bottle-Strange-Thinking-ebook/dp/B001IH6WOM].

[54] Fusion detonators can be built down to 1 kT and less. This is proven technology. A Neutron bomb with 1 kT yield is actually a clean hydrogen bomb without uranium-238 tamper and it is possible to build neutron bombs of much smaller size and to control the neutron emission to heat ratio with other construction materials of the bomb shell.